High voltage (HV) transistors, such as n-type lateral diffused metal oxide semiconductor (nLDMOS) transistors, have various applications, such as for automotive integrated circuits (ICs) and power ICs. The HV transistors operate, for example, at 85 V or greater. Such HV transistors employ reduced surface field (RESURF) techniques. Conventional RESURF techniques require the use of a thick surface epitaxial layer, such as greater than 10 μm. However, the use of a thick epitaxial layer creates problems. For example, thick epitaxial layer results in weak junction isolation, which can cause reliability issues. In addition, the use of a thick epitaxial layer produces high on resistance, negatively impacting device performance.
The present disclosure is directed to reliable HV transistors with reduced on resistance to improve performance.